Audion arrangement for short wave television purposes



ZMZOJMO Feb. 9 1936.

K. SCHLESINGER AUDION ARRANGEMENT FOR SHORT WAVE TELEVISION PURPOSESFiled July 17, 19554 i Unvenioz;

Patented Feb. 4, 1936 AUDION ARRANGEMENT FOR SHORT WAVE TELEVISIONPURPOSES Kurt Schlesinger, Berlin, Germany Application July 17, 1934,Serial No. 735,600 In Germany July 19, 1933 4 Claims.

In the patent application Ser. No. 717,310 there is described an audionarrangement for short-wave and more particularly television purposes,which at the same time causes compensation of the carrier frequency.

It has been found that this arrangement transmits the width of bandnecessary for television purposes merely in incomplete fashion.

The subject matter of the present invention is an additional developmentof the arrangement set forth in application 717,310, which completelyavoids the stated disadvantage.

According to the invention, the circuit linked up with the two controlgrids of the audion is damped to such extent, preferably by the use ofresistances as poor in capacity as possible, that the same no longerreveals any kind of oscillatory properties.

The secondary coil, according to the invention, is so dimensioned thatits natural oscillation is in the vicinity of the unmodulated carrierwave.

A form of embodiment of the arrangement according to the invention isillustrated by way of example in the drawing.

In the same I is the final stage of the intermediate frequency amplifierwith the primary coil 2, 3 the secondary coil, which is earthed at thecentre and is preferably dimensioned in such fashion that its naturaloscillation period is situated in the vicinity of the unmodulatedcarrier wave (for example approximately metres), 6 and I are the audioncondensers, which in accordance with application 717,310 are preferablyvery small, for example are each selected at approximately 3 cm., 8 and9 the grid leak resistances, which may have a size of .1 megohm, I0 isthe audion tube with the cathode IS, the two control grids H and I2,which are preferably passed out separately, the screening grid l4 andthe anode l5, and 4 and 5 are the two damping resistances employed inaccordance with the invention for damping the circuit, which are as poorin capacity as possible and may each have a size of 10 ohms.

The anode and screening potential grid are supplied by a battery l6which however may be substituted by a main supply apparatus and whichmay be separate for each of the valves l and I0.

I claim:

the middle tapping p0 int of said secondary connected to earth, the endsof said secondary connected by way of said condensers to saidcontrolgrids, two leak resistances each connected between one of saidgrids and earth and two damping resistances each connected between theone end of said secondary and earth across the two halves of saidsecondary.

2. An audion arrangement for grid-detection, more particularly in thecase of television signals modulated on a carrier frequency comprising atransformer coupled rier frequency amplifier,

tuned by its natural capacities transformer being to said unmodulatedcarrier frequency,

to the output of a carthe secondary of said a multielectrode valvecomprising an anode, a cathode,

and a screen grid, two

control grids, said cathode being connected to earth, two audioncondensers, the middle tapping point of said secondary connected toearth, the ends of said secondary connected by way of said condensers tosaid control grids, two grid resistances each connected between one ofsaid grids and earth and two damping resistances each connected betweenthe one end of said secondary and earth across the two halves of saidsecondary, said damping resistances being so dimensioned as to preventoscillatory properties.

3. An audion arrangement according to claim 2, characterized in that thedamping resistances are selected at approximately of the grid leakresistances.

4. An audion arrangement according to claim 2, characterized in that thedamping resistances are selected in the order of 10 ohms.

KURT SCHLESINGER.

eLO

